WIMBLEDON, England - Racket bag slung over her shoulder, resignation written across her face, Venus Williams weaved through fans milling about on the sidewalks that players must traverse to get from Court 2 to the Wimbledon locker rooms.

The 32-year-old Williams had just absorbed a lopsided first-round loss at the Grand Slam tournament she once ruled, a poor performance that raised questions about how much longer she will keep playing tennis while dealing with an energy-sapping illness.

She trudged by as her hitting partner, David Witt, was saying: "It's tough to watch sometimes. I think everybody sees it. I don't know what else to say."

Looking lethargic, and rarely showing off the power-based game that carried her to five Wimbledon titles and seven majors overall, Williams departed meekly Monday with a 6-1, 6-3 defeat against 79th-ranked Elena Vesnina of Russia. Only once before — as a teenager making her Wimbledon debut in 1997 — had Williams exited so early at the All England Club.

She hadn't lost in the first round at any Grand Slam tournament in 6½ years. Still, Williams said she'll be at the London Olympics next month and is "planning" to be back at Wimbledon next year.

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"I feel like I'm a great player," Williams said, sounding a tad like someone trying to convince herself.

She repeated that affirmation as she continued: "I am a great player. Unfortunately, I had to deal with circumstances that people don't normally have to deal with in this sport. But I can't be discouraged by that. ... There's no way I'm just going to sit down and give up just because I have a hard time the first five or six freakin' tournaments back."

Later, as part of a slightly testy and awkward exchange with reporters, Williams said: "I'm tough, let me tell you. Tough as nails."

Her loss, in her first match since a second-round ouster at the French Open, was part of an odd Day 1, even if the true tournament favorite in action won easily: Maria Sharapova. Among those sent home were No. 18 Jelena Jankovic, who was rather easily beaten 6-2, 6-4 by Kim Clijsters, a four-time major champion who has been beset by injuries in her last season on tour and, like Williams, is unseeded.

Other seeded losers: No. 23 Andreas Seppi, No. 24 Marcel Granollers and No. 27 Daniela Hantuchova of Slovakia, who was upset by 100th-ranked Jamie Hampton of the United States 6-4, 7-6 (1).

Williams and her younger sister Serena rewrote the way the game was played in the late 1990s and early 2000s, with 120 mph serves and ferocious forehands.

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But Williams hasn't been that player for quite a while now. She announced in August that she had been diagnosed with Sjogren's syndrome, an autoimmune disease that can cause fatigue and joint pain.

Her match against Vesnina was at Court 2, which was built three years ago; Serena complained about having to play on it in 2011. For years prior, the name "Court 2" was assigned to a venue about half the size and a few minutes' walk away, a place known as the "Graveyard of Champions" because of a series of stunning losses by top players: Serena, Jimmy Connors, John McEnroe and Pete Sampras.

Care to guess where Serena is scheduled to play her first-round match Tuesday? Yep, that's right: Court 2.

The older Williams has played only 18 matches in 2012, going 12-6, and looked rather ordinary against Vesnina, who is more accomplished in doubles and never made it past the fourth round at a major tournament in singles.

"Of course I was scared. Not scared, but I was, like, aware of her serve. But I think she didn't serve that well today," said Vesnina, who recalled watching on TV when Williams beat Lindsay Davenport in the 2005 Wimbledon final.

"Maybe for her, it was not one of her best days," Vesnina said about Monday. "But for me, it was one of the best days."

Williams fell behind 5-0, and needed 30 minutes to win a single game. She got broken the first four times she served. She rolled her eyes or shook her head after missed shots. Her father pulled out his camera late in the second set and snapped some photos from the stands, maybe wondering right along with some spectators whether this might be Williams' last singles match at Wimbledon.

At her news conference, Williams was asked what will drive her, given the way she's struggling.

"Am I struggling?" Williams replied. "Am I?"